Edit Bookmark close icon needs hover color

[getsetbro]

Did you search for similar issues before submitting this one?
Yes
Describe the issue you encountered:
The CLOSE icon has no hover effect.
Expected behavior:
"For the X, it should be @buttonColor when idle and #000 (black) when hovered."

• Platform (Win7, 8, 10? macOS? Linux distro?):
  All

• Brave Version:
  0.12.10

• Steps to reproduce:
  1.
  2.
  3.

• Screenshot if needed:
  

• Any related issues:

[bsclifton]

closed via #5954

@getsetbro for future reference, you can use self-closing keywords in the commit and GitHub will auto close the issue on merge

Commit would just need to have text like "Fixes #5954" 😄

[luixxiul]

Test plan: #5954 (comment)